Cross referencing doesn't show anything

Question

I have two files; one is main.tex and the other is supplement.tex and I want to reference table label from supplement.tex to main.tex, I do the following in main.tex:

\usepackage{xr}
\externaldocument{supplement}

No error has shown and I got like this Table ?? (the number didn't appear)

Any help please, I tried different ways while searching but none of them succeed with me.

Answer 1

File documentA.tex

\documentclass{article}
\begin{document}
\section{Section in document A}\label{Asection}
\end{document}

File documentB.tex

\documentclass{article}
\usepackage{xr}
\externaldocument[documentAPrefix-]{documentA}
\begin{document}
\section{Section in document B}\label{Bsection}

This are references to section of document A:

ref: \ref{documentAPrefix-Asection}

pageref: \pageref{documentAPrefix-Asection}

\end{document}

First compile documentA.tex in order to obtain documentA.pdf.

During this compilation, beneath other things, the file documentA.aux comes into being.

Keep that file. Don't have it deleted.

Then compile documentB.tex.

I suggest doing this on the shell-prompt (bash/LXTerminal/command.com/whatever you use) :

On the prompt of your shell change to the directory/folder where both documentA.tex and documentB.tex are saved. (The command for changing to a directory or folder is chdir or cd or the like.)

Then two or three times use the command pdflatex documentA.tex.

Then two or three times use the command pdflatex documentB.tex.

Besides documentA.pdf and documentB.pdf you will get files of extension .log and .aux as well. The .aux-files are of interest for the \externaldocument-command. ;-)